Pawl-and-ratchet mechanism.



No. 824,963. I PATENTED JULY 3, 1906. W. TREWHBLLA.'

PAWL AND RATGHET MECHANISM.

APPLICATION FILED 00T.1'1. 1904.

2 SHEETS-SHEET 1.

No. 824,963. I PATBNTED JULY 3, 1906.

W. TRBWHELLA. PAWL AND RATGHET MECHANISM.

APPLICATION FILED 001117. 190 1.

2 SHEETS--SHEET 2.

Qimww I j flaw? Ma xf jj @140.

, UNITED STATES "PATENT OFFICE.

WILLIAM TREWHELLA, TRENTHAM, VICTORIA, AUSTRALIA, ASSIGNOR TO HIMSELF AND BENJAMIN TREWHELLA, OF TRENTHAM, VICTORIA,

AUSTRALIA.

PAWL-AND-RATCHET MECHANISM.

Specification of Letters Patent.

Patented July 3, 1906 To all whom it may concern:

Be it known that I, WILLIAM TREWHELLA, a subject of the King of Great Britain, residing at Trentham, in the State of Victoria, Commonwealth of Australia, trading with Benjamin Trewhella, a subject of the King of Great Britain, residing at Trentham, aforesaid, as Trewhella Bros., en ineersand ironworkers, have invented an Im roved Pawland-Ratchet Mechanism, of w 'ch the following is a specification.

This invention has relation to pawl-andratchet mechanisms, especially applicable to lifting-jacks and Winches.

A characteristic feature of the invention lies in the combination, with a ratchettoothed element,which may be movable-or stationary, of two actuating-pawls and means for imparting reciprocal motion there:

to to move said element or. to move an element carrying the pawls.

A further characteristic feature of the invention lies in means for holding the pawls in contact with the ratchet-toothed face of said stationary or movable element.

A further characteristic featiu'e of the invention lies in a loose connection of the pawls with the element which serves to reciprocate the same and in combination therewith of means to maintain said connection and at the same time maintain the pawls in contact with the ratchet-toothed face of the movable or stationary element.

A still further characteristic feature of the invention lies in means for reversing the direction of motion of the ratchet-toothed element or of the element which carries the pawls, and, lastly, in the provision of a segmental rocking bearing for the element which imparts reciprocal motion to the pawls; but that my mvention may be fully understood I will describe the same in detail, reference being had to the accompanyin%drawings, in wh1cl 1 igure -1 is a vertical sectional view illustrative of the application of my invention to a lifting-jack of that type in which the rackand movab bar is movable. Fig. 2 is a side elevation, the face-plate of that part of the casing containing t e pawl mechanism being removed, illustratingthe application of my invention to a lifting-lack having a stationary rack-bar e load-supporting casing. Fig. 3

of the application, of the invention to. the ratchet-wheel of a winchor the like. FIGS. 4 and 5 are fragmentary sectional views of ig.

gaging-lever in reversing the direction of motionof the rack-bar. Fig. 6 is a section on line VI VI of Fig. 1, and Fig. 7 is a fragmentary perspective View ofparts shown in Figs. 1 to 5.

Referring more particularly to Fig. 1, c indicates the stationary casing in which the rack-bar 7 has free vertical movement. The casing is of suitable construction to contain the pawls and awl-aotuating mechanism and has preferably two openings 0 and 0, Fig. 2, on one side, normally closed by a faceplate p, Fig. 6, to afford ready access to said mechanism, which is mounted a rockshaft 1, hereinafter referred to as the "rocker.

In the construction of jack under consideration the rocker 1v supports the load, and bearings of sufficient strength must be provided. To avoid undue increase of the thickness of the casing or the connection thereto of bearings or journal-boxes, I provide a sectoral rocking bearing 23, whose convex face 22 bears on and rocks with the rocker 1. The lower end 24 of the web of the rocking bearing is rounded and may be stepped in a corresponding ste formed by the ower contracted portion of the walls of the casin -chamber 0'. step saidIiearing in a suitable wear-plate 24 bolted to the casing, so that it may readily be removed. The front and back walls of the casing-chamber 0' may serve to limit the rocking movements of the bearin 23, or pins or studs 26 may be provided for t e pur ose, as shown The rocker 1 has a partia peripheral groove and nearly circular recesses '3 for the reception of the nearly circular foot ends of two pawls 5 5 of different len ths, said recesses being formed on opposite sides of the center of oscillation of the rocker l and at such angles to said center as to impart to the space between two 'teeth 6 on the rack-bar 7, said rocker being provided with a crank 2, Figs. 2, 4, and 5, as one means of oscillating 1, illustrative of the operation of the disen-' the same. By stepping the pawls in the I is a fragmentary sectional view illustrative I prefer, however, to

pawls reciprocal movements whlch in the case under consideration are equal to the rocker I can dispense with pivot-pins and am enabled to readily remove said pawls, if this becomes necessary.

To prevent longitudinal movement of the awls and at the same time maintain their 1 cc ends constantly in contact with the ratchet-toothed face of the bar, except when moved out of contact therewith for purposes hereinafter described, said pawls are pivotally connected near the rocker to one end of two connecting-rods 10, whose opposite ends are pivotally connected to opposite ends of a balance-lever 9, mounted in the free end of an arm 11, ivoted on a fixed pin 12, on one end of whic is loosely mounted a disengaging-lever 16, hereinafter referred to.

On the in 12 is mounted a coiled spring 13, one en 14, of which exerts a pressure on the arm 11 by which the pawls 5' are held against 'tudinal movement and also in contact wit the ratchet-toothed face of the rack-bar 7 through the balance-lever 9 and links 10 and yet permit reciprocal motion of said pawls, each of which is provided with a pin or stud 19, adapted to be engaged by the inclined-faces 18 of two lugs or pro ections 17 and 17 on the disen aging-lever 16, above referred to, on which the other end, 15, of spring 13 exerts pressure.

On the inner end of a stud or pin rojecting through one of the lateral walls of t e casingchamber 0' is secured an eccentric or cam 20, Fig. 6, (also shownin dotted lines,"Fig. 3,) adapted to engagethe disengaging-lever and move it latera ly, so that its lugs 17 and 17 will be out of reach of the (pins 19 on the pawl 5-, in which position sai lever is held, as shown in Fig. 1, when the rack-bar 7 is being moved upward.

The 0 eration of the jack is as follows: As-

. suming oth pawls 5 in engagement with the rack-bar 7 and the rocker 1 rocked from ri ht to left, the shorter pawl will lift said racker a distance equal to the space between two teeth 6, while the longer pawl will move down a corresponding distance and engage the tooth next below. By reversing the direction of oscillation of the rocker 1 the longer pawl will lift and the shorter pawl will move down and engage the tooth next below, so that at each oscillating movement the rackbar 7 will be raised a distance equal to the s ace between two teeth, the operation being t e same-in the a plication of the pawl mechanism to the ratc et-wheel 8 of a winch, Fig. 3, or the like. In either case the pawls are constantly held in contact with the ratchettoothed face of a movable element 7 or 8 by the action of the spring13 on arm 11 and the action of the latter on the connecting-rods 10 through the balance-lever 9, which is free to follow the movements of the pawls. To reverse the direction of motion of the ratchettoothed element, it is, however, necessary that the pawls 5 be alternately moved out of states tion of the spring 13, and the lug 17 will en-' gage the in 19 of the short pawl 5 and move said paw to the left free from engagement with the rack 7, the weight of the rack having been brought on thelong pawlby a slight movement of the rocker to the right, Fig. 1. If the rocker 1 is now oscillated from right to left in the direction of the arrow, Fi 4, the shorter pawl 5 will move upward wit its pin 19 riding u the lug 17" on lever 16 and engage a toot of the rack-bar 7. At the same time the longer pawl moves down with its pin 19 riding down the lug 17 on the lever 16, which movement carries it out of contact with the rack-bar 7, as shown in Fig. 5. If now rocker 1 is reversed-that is to say, os-

cillated from left to right-the long pawl will moves down, itspin 19 riding down the in clined face of lug 17 on lever 16 and out of engagement with the rack, at which time the long pawl will be in engagement with a tooth up lug on the rack-bar and the bar lowered by one tooth. By again reversing the rocker in the direction of the arrow, Fig. 4, the short pawl will be moved into contact withthe rack-bar, as described, the pawls being alternately moved into and out of contact with the rackbar to lower the latter tooth by tooth, a uniform and reliable movement being thus obtained. i

From theabove description the operation of reversing the ratchet-wheel 8, Fig. 3, can be readily deduced.

In the application of thedescribcd mechanism to a lifting-jack having a stationary rack-bar and a movable load-support the said mechanism is simply inverted, so that by the operation of the pawls the casing a will be caused to move u or down the rackbar, as will be readily un erstood.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is

1. A 'pawl-and-ratchet mechanism comprising a ratchet-toothed element, two actuating-pawls, and means to impart reciprocal motion to said awls; in combination with means to norma ly maintain the actuatingfaces of the pawls in contact with the toothed face of-said ratchet-toothed element, comprising a spring-actuated pivotedarm, a balancelever carried thereby and connecting-rods connecting each end of said lever with an actuating-pawl.

2. A pawland -ratchet mechanism, comprising a ratchet-toothed element, an oscilating element and two actuating-pawls engaging the teeth of said ratchet-toothed element and connected to tlfi oscillating element on opposite sides of its center of oscillation to impart reciprocal movements to the pawls; in combination with a spring-actuated pivoted arm, a lmlance-lever carried thereby, and connecting-rods connecting each end of the balance-lever with an actuating-pawl. 4 3. In a pawl-and-ratchet mechanism, the combination of a casing, a single rack, a cylindrical oscillating element, two pawls mounted on the latter, and a rockable sector mounted in the frame of the casing on which the oscillating element is adapted to roll.

4. A pawl-and-ratchetmechanism, comprising a ratchet-toothed element, an oscilating element, two pawls connected thereto at opposite sides of its center of oscillation to impart reciprocal motion to the pawls, a spring-actuated pivoted arm, a balance-lever carried thereby and connecting-rods connecting'each end of said lever to a pawl to maintain them in contact with the ratchet-toothed element; in combination with means for movin the pawls alternatel out of contact with t e ratchet-toothed e ement, for the purpose set forth.

5. A pawl-and-ratchet mechanism, comprising a ratchet-toothed element, an oscillatmg element, two pawls connected thereto at gpposite sides of its center of oscillation to impart reciprocal motion to the pawls, a spring-actuated pivoted arm, a balance-lever carried thereby, and connecting-rods connecting each end of said lever to a-pawl to maintain them in contact with the ratchettoothed element; in combination with means adapted to be brought into operationat will for moving the pawls alternately out of contact with the ratchet-toothed element, for the purpose set forth; 1

6. A pawl-and-ratchet mechanism, comprising a ratchet-toothed element, an oscillating element, two pawls connected thereto at opposite sides of its center of oscillation to impart reciprocal motion to the pawls, a spring-actuated pivoted arm, a balance-lever carried thereby, and connecting-rods connecting each end of said lever to a pawl to maintain them in contact with the ratchet-toothed element; in combination with a springactu ated disengagin -lever adapted to alternately engage the aw s and move them out of contact with t e ratchet-toothed element, and means to lock said lever against operation.

7. A pawl-and-ratchet mechanism, comrising a ratchet-toothed element, an oscil- Fating element, two pawls connected thereto at opposite sides of its center of oscillation to impart reciprocal motion to said pawl, each provided with a laterall -projecting pin 19, a spring-actuated pivote arm, a balance-lever carried thereb and connecting-rods connecting each end 0 the lever to a pawl to maintain them in contact with the ratchet-toothed element; in combination with a s rin actuaated disengaging-lever provide with two lugs, 17 and 17 having inclined faces 18 adalpted to engage the ms 19 on the aforesai out of contact with the ratchet-toothed element when the oscillating element is rocked to and fro, and means to lock said lever against operation, for the pur ose set forth.

8. The combination with t e rocker 1, its carrier, the long and short pawls having laterally-projecting pins 19 and connected to the rocker as described, and a ratchet-toothed element engaged by said pawls; of the piv-f oted arm 1 1, the balance-leverQ carried there-- by, the connecting-rods 11 connecting each end of said balance-lever to a pawl, the disengagiing-lever 16 having two lugs, 17 and 17 an loosely mounted on pivot of arm 11, and the s ring 13 coiled on said pivot one end of which exerts power on said arm and the other on the disengaging-lever, substantially as andfor the purpose set forth.

9. In a pawl-and-ratchet mechanism, the combination of'a single rack, a cylindrical oscillating element, two actuating pawls pawls and move t e latter alternately mounted on the oscillating element, and means to move both pawls into and out of engagement with the rack, acasing havinga chamber formed therein, and a rockable sector mounted in said chamber on which the oscillating element is adapted to roll.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

WILLIAM TREVi'HELLA. 

